Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
600 PM EDT Sun Oct 16 2022
Valid 12Z Thu Oct 20 2022 - 12Z Mon Oct 24 2022
...Southeast Alaska heavy precipitation threat to renew
Thursday/Friday...
...Active late week/weekend flow from a Bering Sea low into
Western Alaska...
...Overview and Guidance/Predictability Assessment and
Weather/Hazards Highlights...
The 12 UTC GFS/ECMWF/Canadian model solutions seem well clustered
Thursday/Friday and are well supported by ensembles in a pattern
with above normal predictability. In this period, low energies
will keep the Bering Sea/Aleutians then into Western/Southwestern
Alaska and the Interior unsettled with periods of wintry
precipitation and some gusty winds/surf. This includes influence
from Arctic stream upper trough/low energies lingering over
Northwest Alaska. A lingering mean closed low position over the
northern Bering Sea will act to hold onto this active pattern
across the broad region, but offers a less certain daily embedded
weather system focus through next weekend. The compatible and
better run to run consistent 12 UTC GEFS/ECMWF ensemble means seem
to provide a good forecast starting point for these longer time
frames, albeit with less detail consistent with growing
uncertainty.
Meanwhile, a potent system/front working underneath across the
Alaskan Peninsula and Kodiak Island into the Gulf of Alaska will
focus a maritime threat along with wrapping/frontal inflow into
South-central then Southeast Alaska especially into
Thursday/Friday, but also through next weekend with downstream
potent energy transition and system progression. The 12 UTC
GFS/ECMWF/Canadian offer the best clustered system tracks in
Thursday/Friday, but offer varied low strengths. WPC progs have
trended somewhat on the deeper side of full envelope of solutions
given the overall energetic supporting flow pattern. The details
and embedded low interactions and reformations within the flow
remains less certain by the weekend, lending preference from a
composite blend of the 12 UTC GEFS/ECMWF ensemble means to
mitigate the less predictable forecast components.
Schichtel
Additional 3-7 Day Hazard Information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php
WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can also be
found at:
https://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml
https://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html